NEW SUZUKI DF100A / DF115A / DF140A

Haines Suzuki Marine has launched three new mid-range engines to replace the long running and very successful DF100/115/140 series. With the new engines, the Suzuki four-stroke line-up numbers 25 models and stretches from the diminutive 2.5hp through to the thumping 300hp V6.

The new motors, the DF100A, DF115A, and DF140A, are equipped with a range of new features to increase performance and fuel efficiency. Chief among these is the adoption of Suzuki's "Lean Burn" technology first introduced on the DF70/80/90 models.

During the launch of the new engines in Brisbane, assembled journalists were able to sample the largest of the new Suzuki four-strokes, the DF140A. Also on hand for testing was the older model, the hugely successful DF140.

The day started with journalists given the opportunity to trial the older DF140 bolted onto a Signature 543F. Later in the day the old engine was removed and replaced with the new DF140A. Being able to test the two different engines on exactly the same boat (and fitted with the exact same propeller) was very interesting as it made it possible to make a direct comparison.

DESIGN SPECS

- Visually similar - but lots of new bits

At a glance, the new DF100/115/140A engines look similar to their predecessors, but we were told that there are 168 new parts or changes over the previous models.

As before, the three engines share the same engine block, but the displacement of the DF100/115A has been increased from 1,950cc to 2,044cc -- to match the DF140A.

All three engines have an in-line four cylinder, double-overhead cam configuration, a bore x stroke of 86mm x 88mm, a 40 amp alternator, and a gear ratio of 2.59:1. The latter enables these motors to swing a larger propeller and to push heavier loads than most competitor brands.

Weight savings have also been made with the new-series engines. The DF100/115A now weighs 182kg in 20-inch long-shaft configuration - down 7kg on the previous model. The DF140A is the lightest of the trio, with the long-shaft model coming in a 179 kg.

The weights for the DF100/115A are comparable with the major competitor brands in this class, whilst the DF140A is substantially lighter (some 38kg) than its closest competitor, Honda's BF135.

Half of the weight savings can be attributed to the new cowling shape and construction which is 3.6kg lighter than before. The cowling also has a more angled, rakish appearance and a larger air intake for better cooling.

The new Suzuki engines retain the innovative offset drive shaft which positions the powerhead forward of the drive shaft. This design moves the outboard's centre of gravity forward for better weight distribution which can improve the handling on boats that are sensitive to weight or inherently stern heavy.

New features across the board include a 32-bit computer in the ECM module for finer control of the engine's operating systems, an O2 sensor feed-back system for cleaner and more stable emissions, and a new, lighter, more compact vapor separator.

According to Suzuki, the re-designed vapor separator removed the need for a fuel cooler -- which in turn made it possible to streamline the layout of the fuel system for easier maintenance.

In addition, the DF115/140A models now have a knock sensor -- which is a first on Suzuki four-cylinder outboards. The knock sensor will detect abnormal combustion and optimise engine performance for better durability and efficiency.

A useful feature for operating in remote locations -- where fuel quality could be an issue -- is Suzuki's new Water Detecting System built into the fuel filter. When moisture is detected, the skipper is immediately alerted. The filter's design also allows visual inspection.

The new Suzuki outboards are also capable of running on fuel that contains up to 10 per cent ethanol -- although regular 91 octane (or higher) unleaded fuel is recommended.

As noted earlier, the new Suzuki engines utilise Suzuki's Lean Burn Control System that constantly monitors engine performance to deliver a leaner fuel/air mixture for greater efficiency and reduced fuel consumption.

With the lean-burn technology Suzuki claims the new DF140A delivers a 14 per cent improvement in fuel economy over its predecessor.

Suzuki has made additional changes to the new engines to make them more user-friendly and safe-guard against potential damage. With Suzuki's new "One Touch Starting" system, for example, you can simply twist the ignition key once to start the engine. Turning the key repeatedly will not activate the starting system again until it has finished its initial starting cycle.

Similarly, nothing will happen if you turn the key while the engine is running. You might wonder why you would even do that, but these four-stroke engines are so quiet in idle that it can be difficult to hear them running.

An electronic tilt limit system built into the new motors is designed to prevent you from tilting the motor up too high on craft with a small outboard well or those which have the outboard mounted on an external pod with little clearance for the powerhead.

The power trim switch has also been revised so that once the engine has been trimmed all the way down (or up) it will shut off if you still have the trim button depressed.

PRICE AND EQUIPMENT

- New engines, same pricing -- a win for consumers

Suzuki Marine has managed to keep a lid on the pricing for its new trio of four-cylinder four-stroke outboards. Recommended retail prices remain unchanged from the previous models.

The DF100/115/140A are all available in long (20-inch) and extra-long shaft (25-inch) configurations for a total of six models.

An option for the DF100/115A is the recently launched Multi-Function Tiller Handle for those rare applications when a big power tiller-steer outboard is required.

Suzuki's Troll Mode System is a relatively low cost option ($135 plus installation) that may interest anglers as it allows you to raise and lower the engine rpm in idle by 50rpm increments (up to 1,200 rpm) to suit different lure or bait trolling techniques, etc.

As you would expect from a high-tech new four-stroke design, the new DF100/115/140A is equipped with plenty of other features - including a cowl mount trim switch, freshwater flushing system and warnings for most problems that may eventuate.

POWER & PERFORMANCE

- Weather hinders comparison test - but new DF140A still shines

The weather was not kind for our comparison test of the new DF140A against the older DF140 and this made it difficult to draw any meaningful conclusions. The wind was blowing a minimum 15 knots throughout the day and whilst this meant that conditions were similar (very choppy) for both engines, the accuracy of any hard data we gathered is questionable.

For the record, we did GPS recorded speed tests on the Signature 543F with both the old 140hp Suzuki and the new DF140A and found the new model to be a knot or so quicker across most of the rpm range when the test boat was on plane using the exact same 20" pitch stainless steel propeller.

The biggest difference between the two engines was in the middle rpm range, between 3,500 and 4,500 rpm. The DF140A was consistently quicker through this rpm range and this was borne out by seat-of-the-pants gut feel. Most of the assembled journalists noted the DF140A felt stronger in the mid range and that it was able to maintain speed and rpm when running up against wind and waves, whereas the older engine tended to lose rpm and required more throttle work.

In timed acceleration tests, the DF140A was a smidgeon quicker from idle to wide open throttle, though the top speed achieved was virtually identical.

With regard to noise comparisons, to my ear there was not much difference between the old and new engine, though there seemed to be less resonance and vibration with the new DF140A at displacement and semi-planing speeds.

VERDICT

- Evolutionary, not revolutionary

With the DF100/115/140A series Suzuki Marine has taken an evolutionary approach, making genuine improvements to what were already first-class outboard engines.

The new engines are bit a lighter, a bit quieter, easier to use, and more economical. Performance is also up -- not so much in outright top speed, but in the mid range where it counts. Overall I believe Suzuki has got it just right with these new four-strokes; I expect they will be very popular.

Specifications:

Engine type: 4-stroke DOHC 16-valve

Cylinders: In-line 4 cylinder

Fuel Delivery: Multi-Point Sequential EFI

Weight: From 179 kg

Displacement: 2,044 cc

Bore x Stroke: 86 mm x 88 mm

Maximum output: 100/115 hp @ 5,500 rpm, 140 hp @ 6,000 rpm

Operating range DF100/115A: 5,000 - 6,000 rpm

Operating range DF140A: 5,600 - 6,200 rpm

Transom height: L:508 mm (20"), XL:635 mm (25")

Alternator: 12 volt 40 amp

Trim method: Power trim/tilt

Gear ratio: 259:1

Counter rotating: Available DF115/140A (25"XL) only

www.suzukimarine.com.au